Cyclopentanophenanthrene compounds and processes



United States Patent 1 2,776,968 CYCLOPENTANOPHENANTHRENE COMPOUNDS AND PROCESSES Carl Djerassi, Birmingham, Mich and Howard J; Ringold and George Rosenkranz, Mexico City, Mexico, assignors, by mesne assignments, to Syntex S. A., Mexico City, Mexico, a corporation of Mexico No Drawing. Application July 14, 1952, Serial No. 298,834 Claims priority, application Mexico July 26, 1951 l 3 Claims. (Cl. 260-23955) The present application relates to novel cyclopentanophenanthrene compounds and, processes for producing the same. More particularly the present application relates to the production of 11-keto compounds and. particularly of the sapogenin series from the corresponding l2-keto compounds. i

The methods of the. present invention are, therefore, capable of producing l'l-keto compounds which have not heretofore been found in nature and which are. valuable intermediates for the production of ll ketoadrenal hormones. As is well known, hormones of this type, such as cortisone, are extremely valuable therapeutics.

In the United States application of Carl Djerassi and George Rosenkranz, Serial No. 203,015, filed December 27, 1950, there is described a transformation of l2-ket0 sapogenins into the corresponding ll-ke'to l2-hydroxy compounds. The method of the present application relates to the transformation of the compounds thus obtained, as Well as to the transformation of other l'l-keto compounds characterized by the following general 12-hydroxy compounds into the corresponding 11,12 7

diketo compounds and/or the corresponding .l-l-enol derivatives and subsequently the removal of the 'l2-keto group to produce the ll-keto derivative.

A portion of the method involved for the transformation of the ll-keto l2-hydroxy compounds into the corresponding 11,12-diketo compounds and the corresponding ll-enol compounds may be illustrated by the following equation:

formula:

on R

In the above formula R may be alkyh alkylene, oxyalkyl, oxy-alkylene, keto-alkyl, keto-alkylene, carboxy- When R has the above values, then R is, of-course,

hydrogen, since theabove radicals characterize those steroids. with substituents at 17 only. In the case of the sapogenin series, however, both R and R may be linked to either of the following radicals characterizing the 22-iso and 22-normal spirostans:

CHi

u 0 j I,

or CH: O

. It may be noted that the method above outlined is particularly applicable to the sapogenins and is also applicable to the bile acids. and compounds of the pregnane series. For example, in the bile acid seres R may be COOCH3,

0H OH OH Us CE C 40 0000B; OHa-COOOH: 0Hi-oHi.-CO0CH:

Although in the above equation the transformation of 22-isoallospirostan-3,12-diol-11-one to 22-isoallospirostan-3-ol-11,12-dione and the corresponding enol compound A -22-isoa1lospirosten-3,11-diol-12-one is shown, by Way of example the reaction of the present invention above set forth may be applied to similar steroidal 3,12- diol-ll-keto compounds irrespective of the configuration at 3,5 and'22 of the molecule. Thus, while the above compound is a 22-isoallospirostan,"the method may be applied to corresponding 22-normal spirostans. Similarly, the configuration at position 3 may be a or e. In

and R is hydrogen. Similarly, in the pregnane series R may be a v 0HifH-0'H, OHsCIH-OR, or orn(|1=0 and R can be an alkylgroup characteristic of the lower fatty acids or aromatic acids, such as benzoic. R will, of course, be hydrogen. An example of a suitable compound in the pregnane series for this purpose is that disclosed in the form of its ester in co-pending application Serial No. 287,821, filed May 14, 1952 namely, allopregnan-SfiJ2,8-diol-11,20-dione, as may be readily Patented. Jan. 8,

if; 1 t 2,776,968 3 understood, althoughthe aforementioned co-pending apv plication discloses the diacetate of this compound the free I compound may be obtained by conventional methods. steroids of the sapogenin series so that in place of the 22- .In practicing the above method a suitable quantity of isoallospirostan compound above disclosed the corresa 3,12-dihydroxy-l1-keto steroid is dissolved in a lower 5 p g r 1 n S-n rm I mpo n s may be fatty acid, such as glacial acetic acid or propionic acid. ut l z d- Bismuth oxide is then added in slight excess and the mix- In practicing the process above set forth, the spirostan ture is then refluxed for a period of time, such as twenty Compound, as for example 22450anosljirostall'3l9'ol'11,- hours. Soon after the refluxing has started a black p 20-dione, in admixture with the ll-enol form, is dissolved cipitated bismuth starts to form. When the reaction is in a suitable glycol, such as ethylene glycol, and is recomplete the reaction mixture-is cooled and the unreacted fluxed wlth hydmlme hydrate pp if five bismuth salts precipitated by the addition of a suitable Thel'eaftiil' i Imxmre f and a Sultflble Organic Solvent, such as benzerm The solution is than alkali, such as potassium hydroxide is added and the solupassed through a Short column of alumina, preferably tron further heated untll the temperature of the vapors washed with ethyl acetate and the product concentrated 15 reaches for example 190 Thfa'reafter reflux to form a solid residue. The solid product may then be attached and heatm cqntmued for purified or it may be directly treated, as for example proxlmatey four hqurs' Pom pun canon the product was found to be 22-1soallosp1rostan-3fl-ol-ll-one or other with pyridine and acetic anhydride, to form an enol aceequivalent compound in the zzmormal series. i Since the m be a mlxture of the 11,12 The IZ-keto group can also be removed in accordance dlketo correspond??? ll'enol'lz'keto compound' with the present invention by reacting the 11,12-dione in The mixture of nfllz'dlket? and f admixture with its enolic form with a suitable mercaptan, Pounds y be transformed Into the correspondlng such as ethanedithiol to form the corresponding 12-merketo compound as indicated for example by the following captol. Thereafter the resultant compound may be decquation: sulfurized to produce the same type of ll-one previously 0 o H o 1 no 1 nydl' lllle hydrate glycol solution alkali Although in the above equation the production of 22- described. The following equation illustrates, by way of isoallospirostan-3fl-ol-ll-onc is shown by way of illusexample, this form of the present invention:

tration the process is generally applicable to the steroids previously enumerated and is especially applicable to t v Mercaptan ethanedithiol I K H 0 0 Desulfurization 0 Raney nickel no I I g l-fo? Although in the above equation a 22-isoallo compound is shown, the above process is, of course, also applicable to the corresponding 22-normal compounds.

In practicing the step above set forth, the mixture of ketonic and enolic forms of, for example 22-isoallospirostan-3fl-ol-l1,12-dione, in a suitable mercaptan, such as ethanedithiol, is cooled as for example to C. and a slow stream of hydrogen chloride passed into the reaction mixture. After about two hours the flask containing the reaction mixture is placed in a vacuum desiccator for a substantial period of time to eliminate the excess hydrogen chloride. After suitable purification a crystalline mercaptol, namely the 12-cycloethylene mercaptol of 22- isoallospirostan-3B-ol-1l-one was produced. The compound thus produced could be desulfurized by refluxing the same for approximately tWo hours with a suitable solvent, such as ethanol and in the presence of Raney nickel. Upon purification of the resultant product the same ll-one compound resulted as that previously set forth.

The following specific examples serve to illustrate the present invention but are not intended to limit the same:

Example I A solution of 2.0 g. of methyl 3a,12;3-dihydroxy-11- ketocholenate (methyl ester of Marker-Lawsons acid) in 20 cc. of acetic acid was treated with 0.88 g. (1.2 equivalents) of bismuth oxide and the mixture refluxed during four hours. After a short time a black precipitate starts separating. The solution was cooled and the unreacted bismuth salts were precipitated by the addition of 200 cc. of benzene. The solution was passed through a short column of ethyl acetate washed alumina and then concentrated to give a solid residue. It was dissolved in 20 cc. of pyridine and cc. of acetic anhydride and the mixture was left overnight at room temperature and then heated on the steam bath during one hour. The cooled mixture was poured in cold dilute hydrochloric acid and extracted with chloroform, washed with water, with sodium bicarbonate solution and finally with water until neutral. Concentration of the dry chloroform solution gave crystals of methyl 3a,1l-diacetoxy-12-keto-A cholenate, melting point 130-132 C., maximum 244 m1: (10g e 3.97).

- Example II 0.70 g. (1.2 equivalents) of bismuth oxide were added to a solution of 1.67 g. of 22-isoallospirostan-3,l2-diolll-one in cc. of acetic acid and the mixture was refluxed during hours. The formation of a black precipitate of bismuth started after a few minutes. After cooling, the mixture was diluted with 200 cc. of benzene and the solution was passed through a short column of ethyl acetate washed alumina and the filtrate was evaporated to dryness. The solid product obtained after grinding with methanol is a mixture of the ketone 22-isoallospirostan-l1,12-dione-3-ol and the enol A -22-isoallospirosten-3,11-diol-12-one. It gives a strong positive enol reaction with alcoholic ferric chloride and shows (a) :L-O.

The enol acetate was obtained by treating 0.5 of the above product with 5 cc. of acetic anhydride and 3 cc. of pyridine and heating the solution on the steam bath during 3.5 hours. The solution was poured in water and filtered after a few hours. Theenol acetate thus obtainedshowed A maximum 244 mu (log E 3.96). Melting point "188-192 C.

Example III A solution of 6 g. of a mixture of 22-isoallospirostan- 35-o1-11,12-dione and its enolic form, obtained as described in Example II, in 100 cc. of ethyleneglycol was refluxed with 10 cc. of hydrazine hydrate during 5 hours. The mixture was cooled and a solution of 4 g. of potassium hydroxide in 5 cc. of water was added. The solution was then heated in an open flask until the temperature of the vapors reached C.; a reflux condenser was attached and the heating continued four hours more. The mixture was poured in water, extracted with chloroform, washed, dried over sodium sulphate and evaporated to dryness. 4.4 g. of a solid residue was obtained which after several crystallizations from acetone-hexane gave 22-isoallospirostan-3fi-ol-1l-one, melting point 224-225 C., (a) -29 (chloroform); the infrared spectrum (chloroform) showed a band of a free hydroxy group and the characteristic band of the ll-keto group at 1702 cmr The mother liquors yielded a small amount of 22-isoallospirostan-3B,11B-diol, melting point 202204, formed by reduction of the ll-ketone.

Example IV A solution of 540 mg. of the mixture of the ketonic and enolic forms of 22-isoallospirostan-35-ol-11,12-dione in 1.5 cc. ethanedithiol was cooled to 0, and a slow stream of dry hydrogen chloride was passed during two hours. The flask was placed in a vacuum desiccator containing sodium hydroxide and anhydrous calcium chloride and was left overnight in order to eliminate the hydrogen chloride. The residue was taken up in ether and the ether solution was washed with dilute sodium hydroxide solution and water, dried over sodium sulphate and evaporated to dryness. The crystalline mercaptol 12- cycloethylenemercaptol of 22-isoallospirostan-318-01-1lone was obtained by crystallization from hexane-ether; it gave no coloration with ferric chloride, thus indicating that the reaction was complete because the starting material gave a strong reaction (green color) with ferric chloride. The mercaptol had a melting point of 289-29l C. and on further recrystallization of 295-296 C.

The 12-cycloethylenemercaptol of 22-isoallospirostan- 35-01-1 l-one thus obtained, was refluxed during two hours with 40 cc. of ethanol and 4 g. of Raney nickel. The solution was filtered and evaporated to dryness. Upon crystallization of the residue from hexane-acetone, 22-isoallospirostan-3/3-ol-11-one was obtained with a melting point of 224-225 C., identical to the one obtained according to Example III.

We claim:

1. A new compound consisting of the 12-cyc1oethylenemercaptol of 22-isoallospirostan-3fi-ol-1l-one having a melting point of 295-296 C.

2. In a process for the production of 22-isoallospirostan- 3fl-ol-11-one, the step which comprises om'dizing 22-isoallospirostan-3B,12-diol-1l-one with bismuth oxide in the presence of a lower fatty acid to form a mixture of 22- isoallospirostan-l1,12-dione-3-ol and its enol form A 22-isoallospirosten-3 8, 1 1-diol-12-one.

3. A process for the production of 22-isoallospirostan 3fi-ol-11-one which comprises oxidizing 22-isoa1lospirostan-3 8,12-diol-1 l-one with bismuth oxide in the presence of a lower fatty acid to form a mixture of 22-isoallospirostan-11,12-dione-3-ol and its enol form A -22-isoallospirosten-3,6,l1-diol-12-one, treating the mixture with ethanedithiol to form the 12-cycloethylenemercaptol of 22-isoallospirostan-3j8-ol-1l-one and desulfurizing the mercapto with Raney nickel.

References Cited in the file of this patent UNITED STATES PATENTS I Newmann Oct. 20, 1953 OTHER REFERENCES 

1. A NEW COMPOUND CONSISTING OF THE 12-CYCLOETHYLENEMERCAPTOL OF 22-ISOALLOSPIROSTAN-3B-OL-11-ONE HAVING A MELTING POINT OF 295-296* C. 